In the deadliest rampage at an elementary school in U.S. history, 20 first-grade students and six staff members were killed Friday in Newtown, Connecticut. All of the children killed were six and seven years old. They were all shot multiple times. At a vigil for the victims Sunday night, President Obama vowed unspecified action to curb gun violence in the United States. "We can’t tolerate this anymore," Obama said. "These tragedies must end. And to end them, we must change. ... Are we really prepared to say that we’re powerless in the face of such carnage, that the politics are too hard? Are we prepared to say that such violence visited on our children year after year after year is somehow the price of our freedom?" We’re joined by Paul Barrett, assistant managing editor at Bloomberg Businessweek and author of "Glock: The Rise of America’s Gun." [includes rush transcript]

Police say the Newtown gunman, 20-year-old Adam Lanza, used a semi-automatic Bushmaster assault rifle, similar to the M4 carbine used by the U.S. military. He also had two handguns, a Glock 9-millimeter semi-automatic pistol and a SIG Sauer. The massacre occurred just miles from the National Shooting Sports Foundation, the nation’s second-most-powerful pro-gun lobby in the country after the National Rifle Association. We host a debate on gun control between John Velleco, chief federal lobbyist for Gun Owners of America, and Christian Heyne, legislative assistant and grassroots coordinator for the Coalition to Stop Gun Violence. We’re also joined by Paul Barrett, author of "Glock: The Rise of America’s Gun." [includes rush transcript]

Egyptian voters headed to the polls on Saturday in a referendum on a controversial draft constitution. According to unofficial preliminary results, the document passed the first round with 57 percent of the vote with a turnout of just 31 percent. A second round is scheduled for this Saturday in remaining areas. A coalition of human rights groups has called for a revote, citing thousands of complaints of violations at the polls, including a lack of full judicial supervision. Democracy Now! correspondent Sharif Abdel Kouddous reports from Cairo. [includes rush transcript]

Amy Goodman with Denis Moynihan — What price would you pay not to kill another human being? At what point would you commit the offenses allegedly perpetrated by Sgt. Bowe Bergdahl, who was charged Wednesday with desertion and “misbehavior before an enemy?”